I just completed a new (much better) scanning head in preparation for final build and testing, but how do you know if the head is actually moving back and forth?
The answer I came up with is to use reflected laser light to amplify the movement of the scanning head.
To test the new head, I mounted a small mirror (actually a sequin, they’re lighter) in the needle mounting point, shined (shone?) a laser at the mirror to see if I could see movement in the reflected laser point as the scanning head moves back and forth. What I saw was a little movement, but the laser reflection was so diffuse and the movement was so much smaller than the laser reflection that the movement didn’t show well on the video I shot, so you’re going to have to put up with still photos until I acquire better mirrors and/or a more focused laser.